Abstract 222: Exercise Training Prevents Rarefaction of Pial Collaterals, Promotes Cerebral Arterial Remodeling, and Lessens Severity of Stroke in Aging Brain

Variation in anatomic extent of the collateral circulation is an important determinant of variation in the severity of ischemic stroke and efficacy of revascularization therapies. Yet pial collateral number and lumen diameter decrease with age, at least in mice. It is not known if this can be mitigated. We tested whether exercise training can accomplish this and if it also affects diameter of the posterior communicating collalterals (PComs) and primary cerebral arteries (ICA, BA, MCA, ACA, PCA). We randomized 30 male and 30 female, 12 months-old (~40 human years, hy) C57BL/6J mice to either sedentary or voluntary wheel-running (daily distance run was measured). At 25 mos-age (~70 hy), permanent MCA occlusion was followed 24h later by vascular casting after maximal dilation and by determination of infarct volume. Controls for aging were 3 mos-old sedentary mice (~16 hy). Training effect was confirmed by muscle fiber-type switching, body weight and cardiac hypertrophy (all p<0.05). Exercise prevented age-as...